The present invention generally relates to pickup adjusting mechanisms, and more particularly to a pickup adjusting mechanism which is designed to adjust a relative angle between a pickup and a disk-shaped recording medium which is clamped on a turntable.
For example, a disk-shaped recording medium is used as a recording medium capable of storing information such as a database and a software, and the information is reproduced from the disk-shaped recording medium by a laser pickup of an optical disk unit. When the disk-shaped recording medium is placed on a tray and is inserted into the disk unit, the disk-shaped recording medium within the tray is clamped on a turntable. Then, the pickup is guided by guide shafts along a radial direction of the disk-shaped recording medium, and carries out a seek operation.
In this type of a disk unit which is loaded with the disk-shaped recording medium, a relative angle between the pickup and the disk-shaped recording medium must be adjusted so that a distance between a seek operation position of the pickup and the disk-shaped recording medium loaded on the turntable becomes constant, in order to accurately read the information recorded on (that is, pit pattern formed on) the disk-shaped recording medium with a high density.
In other words, in an assembly line of the disk unit, after the turntable, the pickup and the like are assembled, a reflected light from a reference disk which is used for the positional adjustment is detected by the pickup in a state where the reference disk is clamped on the turntable. In this state, the mounting angle of the turntable is adjusted while measuring an angular error of the reflected light from the reference disk detected by the. pickup by a measuring unit (automatic collimator), so that the angle of the reflected light from the reference disk becomes a prescribed value.
A description will be given of a conventional turntable adjusting mechanism applied to the disk unit.
FIG. 1 is a cross sectional view for explaining an important part of the conventional turntable adjusting mechanism.
As shown in FIG. 1, in a conventional turntable adjusting mechanism 1, a motor base 4 for supporting a disk motor 3 which rotates a turntable 2 has a disk-shape, and the position of this motor base 4 is adjusted. The motor base 4 is supported in a state contacting sloping surfaces 6a of base support parts 6 which project from a fixed base 5 which is provided below the motor base 4.
In addition, an eccentric pin 7 for adjusting the angle projects from the fixed base 5. An engaging part 7a provided at the tip end of the eccentric pin 7 penetrates an engaging hole 4a in the motor base 4. Because the outer periphery of the motor base 4 contacts the sloping surfaces of the base support parts 6, when the motor base 4 moves in a horizontal direction, the peripheral edge part in the moving direction is displaced upwards while the peripheral edge part in the opposite direction is displaced downwards.
For this reason, it is possible to simultaneously adjust the inclination angle and the inclination direction of the fixed base 5 by changing the position of the engaging part 7a of the eccentric pin 7 which penetrates the engaging hole 4a in the motor base 4. When making the angle adjustment in a state where a reference disk 8 is clamped on the turntable 2, the mounting angle of the turntable 2 is adjusted while measuring the angular error of the reflected light from the reference disk 8 detected by a pickup (not shown) so that the angle of the reflected light becomes a prescribed value.
However, the conventional turntable adjusting mechanism 1 is constructed to incline the turntable 2 together with the motor base 4. In addition, a clearance along a direction of the height of a tray (not shown) and the turntable 2 is small because of the demands to reduce the thickness of the disk unit. As a result, when the turntable 2 is inclined, there is a problem in that the peripheral edge part of the reference disk 8 which is clamped on the turntable 2 contacts the tray.
On the other hand, it is conceivable to adjust the direction of the guide shafts of the pickup instead of adjusting the position of the turntable 2. But in this conceivable case, it would be necessary to adjust the pair of guide shafts on both sides of the pickup to assume identical angles, and the adjusting operation would become extremely troublesome to carry out.
Accordingly, it is a general object of the present invention to provide a novel and useful pickup adjusting mechanism in which the problems described above are eliminated.
Another and more specific object of the present invention is to provide a pickup adjusting mechanism comprising a turntable on which a disk-shaped recording medium is clamped, a disk motor which drives the turntable, a first base which supports the disk motor, a pickup which reads information recorded on the disk-shaped recording medium, a second base which is supported on the first base and movably supports the pickup, and an angle adjusting part which is provided between the first base and the second base, and adjusts an angle of the pickup with respect to the disk-shaped recording medium clamped on the turntable. According to the pickup adjusting mechanism of the present invention, it is possible to simply adjust, within a short time, the angle of the pickup with respect to the disk-shaped recording medium for the entire second base which is independent of the first base. For this reason, the disk-shaped recording medium will not tilt as in the conventional case, and it is possible to prevent the peripheral edge part of the disk-shaped recording medium from contacting a tray or the like, and to prevent an excessively troublesome and time-consuming adjusting operation.
Still another object of the present invention is to provide a pickup adjusting mechanism, wherein the second base is supported at four positions with respect to the first base, and the angle adjusting part is provided to make an adjustment at three of the four positions. According to the pickup adjusting mechanism of the present invention, it is possible to simply adjust the position of the second base with respect to the first base with a high precision.
A further object of the present invention is to provide a pickup adjusting mechanism, wherein the angle adjusting part includes an adjusting screw which adjusts a gap between the second base and the first base. According to the pickup. adjusting mechanism of the present invention, it is possible to accurately adjust the position of the second base with respect to the first base by simply turning the adjusting screw.
Another object of the present invention is to provide a pickup adjusting mechanism, wherein the second base comprises a guide shaft base which supports a guide shaft guiding a movement of the pickup, and a lead screw base which supports a lead screw driving the pickup. According to the pickup adjusting mechanism of the present invention, it is possible to independently adjust the mounting positions of the guide shaft and the lead screw which movably support the pickup.
Still another object of the present invention is to provide a pickup adjusting mechanism for adjusting a mounting angle of a pickup with respect to a disk-shaped recording medium which is placed on a turntable driven by a disk motor, comprising a first base which supports the disk motor, a second base which is supported on the first base and movably supports the pickup, and an angle adjusting part which is provided between the first base and the second base, and adjusts the mounting angle of the pickup by adjusting a gap between the first base and the second base. According to the pickup adjusting mechanism of the present invention, it is possible to simply adjust, within a short time, the angle of the pickup with respect to the disk-shaped recording medium for the entire second base which is independent of the first base. For this reason, the disk-shaped recording medium will not tilt as in the conventional case, and it is possible to prevent the peripheral edge part of the disk-shaped recording medium from contacting a tray or the like, and to prevent an excessively troublesome and time-consuming adjusting operation.
The angle adjusting part may include an adjusting screw which adjusts the gap between the first base and the second base. In addition, the adjusting screw may penetrate the first base and the second base, and may be adjustable from the first base and the second base. According to the pickup adjusting mechanism of the present invention, it is possible to accurately and simply adjust the mounting position of the pickup within a short time.
A further object of the present invention is to provide a disk unit comprising a turntable on which a loaded disk-shaped recording medium is clamped, a disk motor which drives the turntable, a first base which supports the disk motor, a pickup which at least reads information from the disk-shaped recording medium, a second base which is supported on the first base and movably supports the pickup, and an angle adjusting part which is provided between the first base and the second base, and adjusts an angle of the pickup with respect to the disk-shaped recording medium. According to the disk unit of the present invention, it is possible to simply adjust, within a short time, the angle of the pickup with respect to the disk-shaped recording medium for the entire second base which is independent of the first base. For this reason, the disk-shaped recording medium will not tilt as in the conventional case, and it is possible to prevent the peripheral edge part of the disk-shaped recording medium from contacting a part of the disk unit during the adjustment, and to prevent an excessively troublesome and time-consuming adjusting operation.
The second base may be supported at four positions with respect to the first base, and the angle adjusting part may be provided to make an adjustment at three of the four positions. Moreover, the angle adjusting part may include an adjusting screw which adjusts a gap between the second base and the first base. This adjusting screw may penetrate the first base and the second base, and may be adjustable from the first base and the second base. In these cases, it is possible to accurately and simply adjust the mounting position of the pickup within a short time.
Another object of the present invention is to provide a pickup adjusting mechanism for adjusting a pickup, comprising a disk motor, and a base which supports the disk motor and the pickup, wherein the pickup is supported at four points, and the pickup is fixed at one of the four points and a height position of the pickup is adjustable at remaining three points. According to the pickup adjusting mechanism of the present invention, it is possible to simply adjust, with a high precision and within a short time, the mounting angle of the pickup with respect to the base. It is of course possible to provide this pickup adjusting mechanism in a disk unit.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.